P65 Elevated numbers and size of aggregates of immune cells protects against liver cancer progression

Background Deaths from hepatocellular carcinoma (HCC) are rising. HCC typically develops in the setting of inflammation and chronic liver disease, where the immune environment can either promote or suppress cancer growth. Immune cells infiltrate within HCC are also suspected to play a key role in determining patient responses to treatments, but this is poorly understood. As the therapeutic options for patients with advanced HCC are changing, with a small minority ( Methods Surplus tissues from 58 patients with HCC undergoing diagnostic biopsy, presenting to the Newcastle upon Tyne Hospitals NHS Foundation Trust and recruited to our using SPSS statistical software package, with statistical significance considered as p Results Immune aggregates were detected in HCC in 28/58 patients. Simple ‘presence’ was not significantly associated with any clinicopathological features. However, higher number mm2 aggregates (n=14) was associated with less advanced TNM stage (p=0.015), longer time to radiological progression (20.9 vs 8.0 months, Kaplan-Meier, p=0.033) and longer survival (34.0 vs 20.9 months, p=0.024) compared to lower or absent cases (n=44). Furthermore, mean aggregate area correlated negatively with tumour size (Spearmans Rho -0.413, p=0.029). Patients with larger aggregates were more likely to have a maximal tumour diameter Conclusion Higher numbers and size of immune aggregates were associated with delayed tumour progression, highlighting the need to further define the tumour immune environment in patients with HCC.